기대하다는 an active verb(능동사) and 기대되다 is a passive verb(피동사)
An active verb is a verb which describes an action by a subject with the intention of the subject. It is used with an object.
A passive verb is a verb which describes an action by other person. It is used with a subject.
저 선수의 장래가 기대된다. = 저 선수의 장래를 기대한다.
The future of that athlete is expected = I expect the future of that athlete.
If it is used without an object or a subject, it can be used interchangeably
가장 기대하는 일 = 가장 기대되는 일
The nuance of a passive verb is more humble than an active verb.
You can use 기대되다 in formal situation.
You can use 기대하다 in informal situation.